Potato group. Oval or ovoid granules, showing hilum and concentric rings clearly; cross and colors with selenite usually distinct.
Legume group. Round or oval granules, hilum marked, rings faint, but rendered visible in cases by chromic-acid solution; cross and colors feeble.
Wheat group. Round and oval granules, hilum and rings generally invisible; feebly marked cross and colors.
Sago group. Truncated granules, hilum distinct, rings faint; cross and colors usually faint.
Rice group. Polygonal granules, hilum distinct, rings faint; cross and colors usually faint.